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Topic: I have been reading up on decoction mashing again (Read 8994 times)

Once again I'm doing a lot of reading about mashing and after 20+ pages of various decoction mashing schedules I'm starting to think that it is still more widely used in Germany than I had been thinking. In particular in Bavaria I expect many breweries to still use it especially for dark beers. Being from the brewing school Weihenstephan, the authors have a strong background in Bavarian brewing practices and may have an bias to that style of brewing.

One interesting point that was brought up is that triple decoction mashes can lead to an excessive protein degradation when lighter malts are used but that dark malts, like Munich, don't have this problem since their enzymes are already severely weakened from the kilning process. Though the decoction weakens the enzymes even more this effect is compensated by the better gelatinization of the starches which makes them more accessible to the enzymes.

It also states that a triple decoction may not really be necessary but that, especially for dark beers, it is justified from a beer quality or flavor point of view.

For the decoction form of the Hochkurz mash (dough-in at 140-145 F) the SNR of the malt should be above 40% which is in line with the common wisdom that those malts don't need a protein rest.

Another interesting point was that the decoctions themselves don't need to be boiled. It is sufficient to heat them close to boiling temperatures and hold them there. Many breweries seem to do exactly that. This confirms my intuition of leaving the lid on the boiling decoction and thus being able to turn the burner so low that I get just a simmer. In home brewing, this reduces the risk of scorching the mash significantly and eliminates the need of constant stirring.

This shows that decoctions are more widely used in Germany than I initially thought although I know that neither Bittburger or Warsteiner use them. Nor do I think that they are the cause of the "German flavor" but it illustrates that German brewers strongly believe that a large part of a beers character comes from mashing.

That too found a brief mention. Some breweries used decoction under pressure in order to improve not the quality but the quantity (i.e. efficiency). The practice however has been abandoned because it lead to "hard" and "broad" tasting beers. In some cases even to a straw like taste. I don't exactly know how to paraphrase "hard" and "broad" properly but it is used in the context of beeing the opposite to mild and balanced.

When it comes to the comparison with infusion mashes the author makes a reference to the urge to mash very well modified malts with overly short mashes which can lead to "green" tasting beers with an unsatisfactory quality of the bitterness. In some cases, especially for maltier light colored lagers and Export styles, dough-in at at lower temperature corrected that problem. This meant that instead of doughing in at 62 C the dough in happens at 50 C with an immediate heating to 62 C (1 C/min is common) .

I found that an interesting statement. Nothing is mentioned about the addition of specialty malts to "emulate" decoction flavor in an infusion mash beer. However, that was mentioned in another book by the same author. Given that decoction has little impact on color in light beers I can understand that specialty malts may not be an option in many cases where a brewery wants to move to an infusion mash w/o loosing the character of their brand of beer.

There is also a reference to experiments where decoction and equivalent infusion mashes were compared. In these cases no differences in beer quality were found.

None of this is really conclusive but it does seem to support the findings of some home brewers who compared beers brewed w/ and w/o protein rests and found that the protein rest did give the beer more character.

You, Sir, remain a gentleman and a scholar. This no-boil decoction interests me.

Thanks. If you think about it, none of the changes in the decoction, which we consider a benefit of the decoction process, require evaporation or constant movement of the mash. Maillard reactions depend on temp, pH and concentration of reducing sugars and amino acids. They should be unaffected by agitation. The same is the case for extracting tannins from the husks and gelatization of the starches. Movement is beneficial for the formation of protein break but not the denaturation of the proteins itself. Evaporation drives off DMS, but if that doesn't happen it will happen during the wort boil.

So based on this, is there a decoction mash schedule that you might suggest trying for a helles? If you dough in at 50c, would you immediately pull a decoction and use that to raise to the next step? Would you then do a second decoction?

I think what interests me the most is that I've always wondered in the back of my mind if an electric heating element directly in the bottom of the mash tun might be used to a similar effect as actually pulling a decoction, i.e. a maillard reaction on part of the mash; it's the question of concentration that makes me think it wouldn't work. At least not exactly the same.

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“If one's actions are honest, one does not need the predated confidence of others, only their rational perception.”

I'd pull the first decoction after 10 min, rest it at 70 C for 20 min and simmer it for 15 min. Then return to get 65 C and pull the 2nd decoction after just 10 min. heat to 70 C, rest for 20 min, simmer for 15 min and return too get to 74-76 C. Lauter once the mash is iodine negative. Interesting is the rest of just 10 min after returning the decoction. I haven't done that like this before. But I don't think that this is key for a successful decoction though.

I'm very interested to understand your findings. I recently made a Dusseldorf Altbier using your enhanced double decoction. I kegged and cold crashed and will force carb and let you know the results. Although I don't have anything to compare it with I can get an idea of the effects of the decoction method. As you know I am very interested in discovering the cause of the German "distinct taste" or flavor. Maybe your efforts will shed some light on this issue.

Kai -- why the protein rest for the Helles? I was thinking of doing a decoction Hochkurz mash (145 - 158) for a German Pilsner next weekend since I figured that a) long boiling of the decoction wasn't necessary and b) the protein rest would be unnecessary and maybe even detrimental. What do you think about this?

Kai -- why the protein rest for the Helles? I was thinking of doing a decoction Hochkurz mash (145 - 158) for a German Pilsner next weekend since I figured that a) long boiling of the decoction wasn't necessary and b) the protein rest would be unnecessary and maybe even detrimental. What do you think about this?

The more I read about this the more am I torn between being pro or con protein rest. I brought up the Hochkurz mash as an elegant way of doing decoctions w/o protein rests. However, I haven't done experiments yet where I evaluated the impact of a protein rest. A few reputable brewers have and some of them reported the the protein rest yielded a better beer. This is in contrast to the brewers who report the opposite which report the opposite. At this point I just use it on some beers and not on others w/o having a strong position on its usefulness.

Very interesting info, Kai, especially to a decoction heretic like myself. Do you know how the conclusions about beer quality were reached? Is it just the author's opinion? Is it based on the number of breweries doing decoctions? Is it based on blind tasting panels?

Do you know how the conclusions about beer quality were reached? Is it just the author's opinion?

Many of these statements (though not all) have references to publications. But I don't have access to any of them even tough I'd love to read them myself. The statements w/o references might reflect the experience and position of the authors.

In the past I had the chance to ask German brewers about decoction mashing and the taste difference and the conclusion so far is that the differences are rather small. It is still unclear to me to what extend modern decoction mashing is done for tradition, out of technical necessity or for beer quality reasons. To me the decoction debate lives on and I encourage interested brewers to take a look at practical mashing options and try some of them. Though single infusion works in most cases I don't want the home brewing community to get stuck in the idea that there is a one-size-fits all mash schedule.

It should not be forgotten that compared to fermentation, the mash schedule has a much smaller impact on the final beer quality and that you cannot make up for poor beer fermentation with any of the things you do in the brewhouse.

To me the decoction debate lives on and I encourage interested brewers to take a look at practical mashing options and try some of them. Though single infusion works in most cases I don't want the home brewing community to get stuck in the idea that there is a one-size-fits all mash schedule.

In spite of my skepticism about decoction, I completely agree with this. I think every homebrewer who's interested in the subject should try a number of different mash schedules and decide for themselves. The one "fly in the ointment" I've found is that too many people don't make an objective decision based on repeated blind tasting. Even better is to do that with a number of tasters. But if someone enjoys doing decoctions, far be it from me to tell them not to!

To me the decoction debate lives on and I encourage interested brewers to take a look at practical mashing options and try some of them. Though single infusion works in most cases I don't want the home brewing community to get stuck in the idea that there is a one-size-fits all mash schedule.

In spite of my skepticism about decoction, I completely agree with this. I think every homebrewer who's interested in the subject should try a number of different mash schedules and decide for themselves. The one "fly in the ointment" I've found is that too many people don't make an objective decision based on repeated blind tasting. Even better is to do that with a number of tasters. But if someone enjoys doing decoctions, far be it from me to tell them not to!

+1

Keeping an open mind is key to making improvements in any process and "The proof is in the pudding". Until the process has been tested through repeated blind tasting...the jury is still out. I am not convinced one way or the other on the effects of decoction mashing, but I have a real interest in finding out the truth.